serial: Add interface to set reference oscillator frequency

Many (most?) serial interfaces have a programmable
clock which provides the reference frequency ("baudbase").
So a fixed baudbase which is only set once can be wrong.

omap1.c is an example which could use the new interface
to change baudbase when the programmable clock changes.
ar7 system emulation (still not part of standard QEMU)
is similar to omap and already uses serial_set_frequency.

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/hw/pc.h b/hw/pc.h
index 15fff8d1036901d9b9406962520dc6f0b40f3d80..03ffc915361114fefa99abcf0b3cc54e56704b09 100644 (file)
--- a/hw/pc.h
+++ b/hw/pc.h
@@ -13,6 +13,7 @@ SerialState *serial_mm_init (target_phys_addr_t base, int it_shift,
                              qemu_irq irq, int baudbase,
                              CharDriverState *chr, int ioregister);
 SerialState *serial_isa_init(int index, CharDriverState *chr);
+void serial_set_frequency(SerialState *s, uint32_t frequency);
 
 /* parallel.c */
 

diff --git a/hw/serial.c b/hw/serial.c
index fa12dcc0752d5af8ec63d1384dde33218d178deb..006326056912ab3dba6d829232accde15f1795c1 100644 (file)
--- a/hw/serial.c
+++ b/hw/serial.c
@@ -730,6 +730,13 @@ static void serial_init_core(SerialState *s)
                           serial_event, s);
 }
 
+/* Change the main reference oscillator frequency. */
+void serial_set_frequency(SerialState *s, uint32_t frequency)
+{
+    s->baudbase = frequency;
+    serial_update_parameters(s);
+}
+
 static const int isa_serial_io[MAX_SERIAL_PORTS] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8 };
 static const int isa_serial_irq[MAX_SERIAL_PORTS] = { 4, 3, 4, 3 };